![f0018-01](https://article-imgs.scribdassets.com/8eqs1fnx34bzmfkn/images/fileOAHWEZW4.jpg)
If you look carefully at a mountain range, you can often see how layers of rock have been deformed into structures that look like “waves” – these waves are called folds by geologists. The folding is caused by forces operating in the Earth’s crust.
![f0018-03](https://article-imgs.scribdassets.com/8eqs1fnx34bzmfkn/images/fileK0ECIFDN.jpg)
A majority of earthquake and volcanic activity occurs above plate boundaries.
![f0018-02](https://article-imgs.scribdassets.com/8eqs1fnx34bzmfkn/images/filePNT6CSM2.jpg)
You can